Terminal device, base station device, transmitting method and receiving method

ABSTRACT

The present invention pertains to a terminal device, which, when ARQ is used for communication that uses an uplink unit band and a plurality of downlink unit bands associated with the uplink unit band, and when a transmission mode that supports up to 2 TB in a PCell is set in the terminal, is capable of reducing the amount of signaling from a base station while eliminating a lack of PUCCH resources when semi-permanent scheduling (SPS) is used in the PCell. A control unit in this device selects one value among values obtained by adding 1 to four PUCCH resource indexes, which have been preset for PUCCH resource 1 by the base station, on the basis of values for transmission power control information (TPC command for PUCCH) in a PDCCH, for which notification has been received at the start of SPS.

BACKGROUND Technical Field

The present invention relates to a terminal apparatus, a base stationapparatus, a transmitting method, and a receiving method.

Description of the Related Art

3GPP LTE employs Orthogonal Frequency Division Multiple Access (OFDMA)as a downlink communication scheme. In radio communication systems towhich 3GPP LTE is applied, base stations transmit synchronizationsignals (i.e., Synchronization Channel: SCH) and broadcast signals(i.e., Broadcast Channel: BCH) using predetermined communicationresources. Meanwhile, each terminal finds an SCH first and therebyensures synchronization with a base station. Subsequently, the terminalreads BCH information to acquire base station-specific parameters (see,Non-Patent Literatures (hereinafter, abbreviated as NPL) 1, 2 and 3).

In addition, upon completion of the acquisition of the basestation-specific parameters, each terminal sends a connection request tothe base station to thereby establish a communication link with the basestation. The base station transmits control information via PhysicalDownlink Control Channel (PDCCH) as appropriate to the terminal withwhich a communication link has been established.

The terminal performs “blind-determination” on each of a plurality ofpieces of control information included in the received PDCCH signals(i.e., Downlink (DL) Assignment Control Information: also referred to asDownlink Control Information (DCI)). To put it more specifically, eachpiece of the control information includes a Cyclic Redundancy Check(CRC) part and the base station masks this CRC part using the terminalID of the transmission target terminal. Accordingly, until the terminaldemasks the CRC part of the received piece of control information withits own terminal ID, the terminal cannot determine whether or not thepiece of control information is intended for the terminal. In thisblind-determination, if the result of demasking the CRC part indicatesthat the CRC operation is OK, the piece of control information isdetermined as being intended for the terminal.

Moreover, in 3GPP LTE, Automatic Repeat Request (ARQ) is applied todownlink data to terminals from a base station. To put it morespecifically, each terminal feeds back response signals indicating theresult of error detection on the downlink data to the base station. Eachterminal performs a CRC on the downlink data and feeds backAcknowledgment (ACK) when CRC=OK (no error) or Negative Acknowledgment(NACK) when CRC=Not OK (error) to the base station as response signals.An uplink control channel such as Physical Uplink Control Channel(PUCCH) is used to feed back the response signals (i.e., ACK/NACKsignals (hereinafter, may be referred to as “A/N,” simply)).

The control information to be transmitted from a base station hereinincludes resource assignment information including information onresources assigned to the terminal by the base station. As describedabove, PDCCH is used to transmit this control information. The PDCCHincludes one or more L1/L2 control channels (L1/L2 CCH). Each L1/L2 CCHconsists of one or more Control Channel Elements (CCE). To put it morespecifically, a CCE is the basic unit used to map the controlinformation to PDCCH. Moreover, when a single L1/L2 CCH consists of aplurality of CCEs (2, 4 or 8), a plurality of contiguous CCEs startingfrom a CCE having an even index are assigned to the L1/L2 CCH. The basestation assigns the L1/L2 CCH to the resource assignment target terminalin accordance with the number of CCEs required for indicating thecontrol information to the resource assignment target terminal. The basestation maps the control information to physical resources correspondingto the CCEs of the L1/L2 CCH and transmits the mapped controlinformation.

In addition, CCEs are associated with component resources of PUCCH(hereinafter, may be referred to as “PUCCH resource”) in a one-to-onecorrespondence. Accordingly, a terminal that has received an L1/L2 CCHidentifies the component resources of PUCCH that correspond to the CCEsforming the L1/L2 CCH and transmits response signals to the base stationusing the identified resources. However, when the L1/L2 CCH occupies aplurality of contiguous CCEs, the terminal transmits the responsesignals to the base station using a PUCCH component resourcecorresponding to a CCE having a smallest index among the plurality ofPUCCH component resources respectively corresponding to the plurality ofCCEs (i.e., PUCCH component resource associated with a CCE having aneven numbered CCE index). In this manner, the downlink communicationresources are efficiently used.

Moreover, 3GPP LTE employs a scheduling scheme of assigning radioresources in a constant cycle for packet data in VoIP, streaming, andthe like involving a transmission rate that is constant to some extent,instead of employing a best-effort scheduling scheme (dynamicscheduling), which dynamically assigns radio resources to achieve higherefficiency. This scheduling scheme is referred to, for example,persistent scheduling or semi-persistent scheduling (SPS). In SPS,activation and release are indicated through a PDCCH. Once SPS isactivated, a base station transmits a Physical Downlink Shared Channel(PDSCH) in a constant cycle and no longer indicates a PDCCH with respectto the PDSCH scheduled by SPS. In SPS, since the base station and aterminal perform transmission and reception at known transmission timingas described above, downlink scheduling information (DL schedulinginformation) can be reduced, which in turn makes it possible toeffectively utilize downlink radio resources. During SPS transmission,the terminal feeds back response signals to the base station. Thisfeedback of the response signals is performed using a PUCCH resourcecorresponding to one of four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) )that are set in advance in a one-to-one correspondence with (two-bit)values of a transmission power control (TPC) command in the PDCCHindicating the activation of SPS.

As illustrated in FIG. 1, a plurality of response signals transmittedfrom a plurality of terminals are spread using a Zero Auto-correlation(ZAC) sequence having the characteristic of zero autocorrelation intime-domain, a Walsh sequence and a discrete Fourier transform (DFT)sequence, and are code-multiplexed in a PUCCH. In FIG. 1, (W₀, W₁, W₂,W₃) represent a length-4 Walsh sequence and (F₀, F₁, F₂) represent alength-3 DFT sequence. As illustrated in FIG. 1, ACK or NACK responsesignals are primary-spread over frequency components corresponding to 1SC-FDMA symbol by a ZAC sequence (length-12) in frequency-domain. To putit more specifically, the length-12 ZAC sequence is multiplied by aresponse signal component represented by a complex number. Subsequently,the ZAC sequence serving as the response signals and reference signalsafter the primary-spread is secondary-spread in association with each ofa Walsh sequence (length-4: W₀-W₃ (may be referred to as Walsh CodeSequence)) and a DFT sequence (length-3: F₀-F₂). To put it morespecifically, each component of the signals of length-12 (i.e., responsesignals after primary-spread or ZAC sequence serving as referencesignals (i.e., Reference Signal Sequence) is multiplied by eachcomponent of an orthogonal code sequence (i.e., orthogonal sequence:Walsh sequence or DFT sequence). Moreover, the secondary-spread signalsare transformed into signals of length-12 in the time-domain by inversefast Fourier transform (IFFT). A CP is added to each signal obtained byIFFT processing, and the signals of one slot consisting of seven SC-FDMAsymbols are thus formed.

The response signals from different terminals are spread using ZACsequences each corresponding to a different cyclic shift value (i.e.,index) or orthogonal code sequences each corresponding to a differentsequence number (i.e., orthogonal cover index (OC index)). An orthogonalcode sequence is a combination of a Walsh sequence and a DFT sequence.In addition, an orthogonal code sequence is referred to as a block-wisespreading code in some cases. Thus, base stations can demultiplex thecode-multiplexed plurality of response signals using the related artdespreading and correlation processing (see, NPL 4).

However, it is not necessarily true that each terminal succeeds inreceiving downlink assignment control signals because the terminalperforms blind-determination in each subframe to find downlinkassignment control signals intended for the terminal. When the terminalfails to receive the downlink assignment control signals intended forthe terminal on a certain downlink component carrier, the terminal wouldnot even know whether or not there is downlink data intended for theterminal on the downlink component carrier. Accordingly, when a terminalfails to receive the downlink assignment control signals intended forthe terminal on a certain downlink component carrier, the terminalgenerates no response signals for the downlink data on the downlinkcomponent carrier. This error case is defined as discontinuoustransmission of ACK/NACK signals (DTX of response signals) in the sensethat the terminal transmits no response signals.

In 3GPP LTE systems (may be referred to as “LTE system,” hereinafter),base stations assign resources to uplink data and downlink data,independently. For this reason, in the 3GPP LTE system, terminals (i.e.,terminals compliant with LTE system (hereinafter, referred to as “LTEterminal”)) encounter a situation where the terminals need to transmituplink data and response signals for downlink data simultaneously in theuplink. In this situation, the response signals and uplink data from theterminals are transmitted using time-division multiplexing (TDM). Asdescribed above, the single carrier properties of transmission waveformsof the terminals are maintained by the simultaneous transmission ofresponse signals and uplink data using TDM.

In addition, as illustrated in FIG. 2, the response signals (i.e.,“A/N”) transmitted from each terminal partially occupy the resourcesassigned to uplink data (i.e., Physical Uplink Shared CHannel (PUSCH)resources) (i.e., response signals occupy some SC-FDMA symbols adjacentto SC-FDMA symbols to which reference signals (RS) are mapped) and arethereby transmitted to a base station in time-division multiplexing(TDM). In FIG. 2, however, “subcarriers” in the vertical axis of thedrawing are also termed as “virtual subcarriers” or “time contiguoussignals,” and “time contiguous signals” that are collectively inputtedto a discrete Fourier transform (DFT) circuit in a SC-FDMA transmitterare represented as “subcarriers” for convenience. To put it morespecifically, optional data of the uplink data is punctured due to theresponse signals in the PUSCH resources. Accordingly, the quality ofuplink data (e.g., coding gain) is significantly reduced due to thepunctured bits of the coded uplink data. For this reason, base stationsinstruct the terminals to use a very low coding rate and/or to use verylarge transmission power so as to compensate for the reduced quality ofthe uplink data due to the puncturing.

Meanwhile, the standardization of 3GPP LTE-Advanced for realizing fastercommunications than 3GPP LTE has started. 3GPP LTE-Advanced systems (maybe referred to as “LTE-A system,” hereinafter) follow 3GPP LTE systems(may be referred to as “LTE system,” hereinafter). 3GPP LTE-Advanced isexpected to introduce base stations and terminals capable ofcommunicating with each other using a wideband frequency of 40 MHz orgreater to realize a downlink transmission rate up to 1 Gbps or above.

In the LTE-A system, in order to simultaneously achieve backwardcompatibility with the LTE system and ultra-high-speed communicationsseveral times faster than transmission rates in the LTE system, theLTE-A system band is divided into “component carriers” of 20 MHz orbelow, which is the bandwidth supported by the LTE system. In otherwords, the “component carrier” is defined herein as a band having amaximum width of 20 MHz and as the basic unit of communication band.Moreover, “component carrier” in downlink (hereinafter, referred to as“downlink component carrier”) is defined as a band obtained by dividinga band according to downlink frequency bandwidth information in a BCHbroadcasted from a base station or as a band defined by a distributionwidth when a downlink control channel (PDCCH) is distributed in thefrequency domain. In addition, “component carrier” in uplink(hereinafter, referred to as “uplink component carrier”) may be definedas a band obtained by dividing a band according to uplink frequency bandinformation in a BCH broadcasted from a base station or as the basicunit of a communication band of 20 MHz or below including a PhysicalUplink Shared Channel (PUSCH) in the vicinity of the center of thebandwidth and PUCCHs for LTE on both ends of the band. In addition, theterm “component carrier” may be also referred to as “cell” in English in3GPP LTE-Advanced and may be abbreviated as CC(s).

The LTE-A system supports communications using a band obtained byaggregating several component carriers, so called “carrier aggregation.”In general, throughput requirements for uplink are different fromthroughput requirements for downlink. For this reason, so called“asymmetric carrier aggregation” has been also discussed in the LTE-Asystem. In asymmetric carrier aggregation, the number of componentcarriers configured for any terminal compliant with the LTE-A system(hereinafter, referred to as “LTE-A terminal”) differs between uplinkand downlink. In addition, the LTE-A system supports a configuration inwhich the numbers of component carriers are asymmetric between uplinkand downlink, and the component carriers have different frequencybandwidths.

FIG. 3 is a diagram provided for describing asymmetric carrieraggregation and a control sequence applied to individual terminals. FIG.3 illustrates a case where the bandwidths and numbers of componentcarriers are symmetric between the uplink and downlink of base stations.

In FIG. 3, a configuration in which carrier aggregation is performedusing two downlink component carriers and one uplink component carrieron the left is set for terminal 1, while a configuration in which thetwo downlink component carriers identical with those used by terminal 1are used but uplink component carrier on the right is used for uplinkcommunications is set for terminal 2.

Referring to terminal 1, an LTE-A base station and an LTE-A terminalincluded in the LTE-A system transmit and receive signals to and fromeach other in accordance with the sequence diagram illustrated in FIG.3A. As illustrated in FIG. 3A, (1) terminal 1 is synchronized with thedownlink component carrier on the left when starting communications withthe base station and reads information on the uplink component carrierpaired with the downlink component carrier on the left from a broadcastsignal called system information block type 2(SIB2). (2) Using thisuplink component carrier, terminal 1 starts communications with the basestation by transmitting, for example, a connection request to the basestation. (3) Upon determining that a plurality of downlink componentcarriers need to be assigned to the terminal, the base station instructsthe terminal to add a downlink component carrier. However, in this case,the number of uplink component carriers is not increased, and terminal1, which is an individual terminal, starts asymmetric carrieraggregation.

In addition, in the LTE-A system to which carrier aggregation isapplied, a terminal may receive a plurality of pieces of downlink dataon a plurality of downlink component carriers at a time. In LTE-A,studies have been carried out on channel selection (also referred to as“multiplexing”), bundling and a discrete Fourier transform spreadorthogonal frequency division multiplexing (DFT-S-OFDM) format as amethod of transmitting a plurality of response signals for the pluralityof pieces of downlink data. In channel selection, not only symbol pointsused for response signals, but also the resources to which the responsesignals are mapped are varied in accordance with the pattern for resultsof the error detection on the plurality of pieces of downlink data.Compared with channel selection, in bundling, ACK or NACK signalsgenerated according to the results of error detection on the pluralityof pieces of downlink data are bundled (i.e., bundled by calculating alogical AND of the results of error detection on the plurality of piecesof downlink data, provided that ACK=1 and NACK=0), and response signalsare transmitted using one predetermine resource. In transmission usingthe DFT-S-OFDM format, a terminal jointly encodes (i.e., joint coding)the response signals for the plurality of pieces of downlink data andtransmits the coded data using the format (see, NPL 5).

More specifically, channel selection is a technique that varies not onlythe phase points (i.e., constellation points) for the response signalsbut also the resources used for transmission of the response signals(may be referred to as “PUCCH resource,” hereinafter) on the basis ofwhether the results of error detection on the plurality of pieces ofdownlink data received on the plurality of downlink component carriersare each an ACK or NACK as illustrated in FIG. 4. Meanwhile, bundling isa technique that bundles ACK/NACK signals for the plurality of pieces ofdownlink data into a single set of signals and thereby transmits thebundled signals using one predetermined resource (see, NPLs 6 and 7).

The following two methods are considered as a possible method oftransmitting response signals in uplink when a terminal receivesdownlink assignment control information via a PDCCH and receivesdownlink data.

One of the methods is to transmit response signals using a PUCCHresource associated in a one-to-one correspondence with a controlchannel element (CCE) occupied by the PDCCH (i.e., implicit signaling)(hereinafter, method 1). More specifically, when DCI intended for aterminal served by a base station is allocated in a PDCCH region, eachPDCCH occupies a resource consisting of one or a plurality of contiguousCCEs. In addition, as the number of CCEs occupied by a PDCCH (i.e., thenumber of aggregated CCEs: CCE aggregation level), one of aggregationlevels 1, 2, 4 and 8 is selected according to the number of informationbits of the assignment control information or a propagation pathcondition of the terminal, for example. This resource is associated in aone-to-one correspondence with and implicitly assigned to a CCE index,and thus may be referred to as implicit resource.

The other method is to previously indicate a PUCCH resource to eachterminal from a base station (i.e., explicit signaling) (hereinafter,method 2). To put it differently, each terminal transmits responsesignals using the PUCCH resource previously indicated by the basestation in method 2. This resource is explicitly indicated in advance bythe base station, and thus may be referred to as explicit resource.

In addition, as illustrated in FIG. 4, one of the two downlink componentcarriers is paired with one uplink component carrier to be used fortransmission of response signals. The downlink component carrier pairedwith the uplink component carrier to be used for transmission ofresponse signals is called a primary component carrier (PCC) or aprimary cell (PCell). In addition, the downlink component carrier otherthan the primary component carrier is called a secondary componentcarrier (SCC) or a secondary cell (SCell). For example, PCC (or PCell)is the downlink component carrier used to transmit broadcast informationabout the uplink component carrier on which response signals to betransmitted (e.g., system information block type 2 (SIB 2)).

Meanwhile, in channel selection, a PUCCH resource in an uplink componentcarrier associated in a one-to-one correspondence with the top CCE indexof the CCEs occupied by the PDCCH indicating the PDSCH in PCC (PCell)(i.e., PUCCH resource in PUCCH region 1 in FIG. 4) is assigned (implicitsignaling).

Next, a description will be provided regarding ARQ control using channelselection when the asymmetric carrier aggregation described above isapplied to terminals with reference to FIGS. 4, 5 and 6.

In a case where a component carrier group (may be referred to as“component carrier set” in English) consisting of downlink componentcarrier 1 (PCell), downlink component carrier 2 (SCell) and uplinkcomponent carrier 1 is configured for terminal 1 as illustrated in FIG.4, after downlink resource assignment information is transmitted via aPDCCH of each of downlink component carriers 1 and 2, downlink data istransmitted using the resource corresponding to the downlink resourceassignment information.

In channel selection, when terminal 1 succeeds in receiving the downlinkdata on component carrier 1 (PCell) but fails to receive the downlinkdata on component carrier 2 (SCell) (i.e., when the result of errordetection on component carrier 1 (PCell) is an ACK and the result oferror detection on component carrier 2 (SCell) is a NACK), the responsesignals are mapped to a PUCCH resource in PUCCH region 1 to beimplicitly signaled, while a first phase point (e.g., phase point (1, 0)and/or the like) is used as the phase point of the response signals. Inaddition, when terminal 1 succeeds in receiving the downlink data oncomponent carrier 1 (PCell) and also succeeds in receiving the downlinkdata on component carrier 2 (SCell), the response signals are mapped toa PUCCH resource in PUCCH region 2 while the first phase point is used.That is, in the configuration including two downlink component carrierswith a transmission mode that supports only one transport block (TB) perdownlink component carrier, the results of error detection arerepresented in four patterns (i.e., ACK/ACK, ACK/NACK, NACK/ACK, andNACK/NACK). Hence, the four patterns can be represented by combinationsof two PUCCH resources and two kinds of phase points (e.g., binary phaseshift keying (BPSK) mapping).

In addition, when terminal 1 fails to receive DCI on component carrier 1(PCell) but succeeds in receiving downlink data on component carrier 2(SCell) (i.e., the result of error detection on component carrier 1(PCell) is a DTX and the result of error detection on component carrier2 (SCell) is an ACK), the CCEs occupied by the PDCCH intended forterminal 1 cannot be identified. Thus, the PUCCH resource included inPUCCH region 1 and associated in a one-to-one correspondence with thetop CCE index of the CCEs cannot be identified either. Accordingly, inthis case, in order to report an ACK, which is the result of errordetection on component carrier 2, the response signals need to be mappedto an explicitly signaled PUCCH resource included in PUCCH region 2 (maybe referred to as “to support implicit signaling,” hereinafter).

To be more specific, FIG. 5 and FIG. 6 each illustrate mapping ofpatterns for the results of error detection in the configurationincluding two downlink component carriers (one PCell and one SCell)with:

(a) the transmission mode that supports only 1 TB for each downlinkcomponent carrier;

(b) the transmission mode that supports only 1 TB for the downlinkcomponent carrier of PCell and the transmission mode that supports up to2 TBs for the downlink component carrier of SCell;

(c) the transmission mode that supports up to 2 TBs for the downlinkcomponent carrier of PCell and the transmission mode that supports only1 TB for the downlink component carrier of SCell; and

(d) the transmission mode that supports up to 2 TBs for each downlinkcomponent carrier. FIG. 7 illustrates the mapping of each of FIG. 5 andFIG. 6 in the form of a table (hereinafter, may be referred to as“mapping table” or “transmission rule table”).

For downlink data channel (Physical Downlink Shared Channel: PDSCH)transmission in PCell, the PUCCH resource indicating method disclosed inNPL 8 uses an implicit resource when dynamic scheduling is used forPCell. Meanwhile, when SPS is used for PCell, this method uses one offour PUCCH resources set in advance in a one-to-one correspondence withvalues of a TPC command for PUCCH that is included in the PDCCHindicating the activation of SPS, similarly to 3GPP LTE. For PDSCHtransmission in SCell, this method uses an implicit resource when aPDCCH corresponding to a PDSCH in SCell is placed in PCell (hereinafter,may be referred to as “cross-carrier scheduling from PCell to SCell”)and uses an explicit resource when no cross-carrier scheduling fromPCell to SCell is configured.

In the method disclosed in NPL 8, for PDSCH transmission in SCell whenno cross-carrier scheduling from PCell to SCell is configured, a PDCCHcorresponding to a PDSCH in SCell is placed in SCell. In such a case, ifan implicit resource, which is implicitly indicated on the basis of theCCE index, is used, the CCE index of a PDCCH placed in PCell that isintended for the target terminal or a different terminal may be the sameas the CCE of the PDCCH placed in SCell that is intended for the targetterminal. In this case, the same PUCCH resource is indicated to bothPCell and SCell, and a collision of response signals occurs unfavorably.For this reason, an explicit resource is used for PDSCH transmission inSCell when no cross-carrier scheduling from PCell to SCell isconfigured. On the other hand, for PDSCH transmission in SCell whencross-carrier scheduling from PCell to SCell is configured, the PDCCHcorresponding to the PDSCH in SCell is placed in PCell. In this case,there is no such case where a CCE occupied by a different PDCCH intendedfor the same terminal or by a PDCCH intended for another terminal isused for the CCE occupied by the abovementioned PDCCH. Hence, animplicit resource can be used for the PDSCH transmission in SCell whencross-carrier scheduling from PCell to SCell is configured.

The PUCCH resource indicating method disclosed in NPL 9 uses oneimplicit resource for non-MIMO DCI and two implicit resources for MIMODCI for PDSCH transmission in PCell. This method uses an explicitresource for PDSCH transmission in SCell.

In the case of NPL 9, 1 CCE includes 36 resource elements (REs), and 72bits can be thus transmitted per CCE when QPSK mapping for each resourceelement is used. Non-MIMO DCI has a smaller number of bits than MIMODCI, and thus can be transmitted using 1 CCE. In contrast, MIMO DCI hasa larger number of bits than non-MIMO DCI, and is generally transmittedusing 2 or more CCEs in order to reduce the error rate of PDCCH.Accordingly, in the case of NPL 9, one implicit resource is used fornon-MIMO DCI in consideration of PDCCH transmission using 1 or moreCCEs, whereas two implicit resources are used for MIMO DCI inconsideration of PDCCH transmission using 2 or more CCEs.

If two implicit resources are used for PDCCH transmission using 1 CCE,because the implicit resources are associated in a one-to-onecorrespondence with the CCE indexes, 2 CCEs need to be occupied for thePUCCH resource indication although the PDCCH transmission occupies only1 CCE. In such a case where a larger number of CCEs than the number ofCCEs occupied by PDCCH are occupied for the PUCCH resource indication, aPDCCH for another terminal cannot be assigned to these CCEs, whichresults in restrictions on PDCCH scheduling in the base station.

CITATION LIST Non-Patent Literature

NPL 1

-   -   3GPP TS 36.211 V9.1.0, “Physical Channels and Modulation        (Release 9),” May 2010

NPL 2

-   -   3GPP TS 36.212 V9.2.0, “Multiplexing and channel coding (Release        9),” June 2010

NPL 3

-   -   3GPP TS 36.213 V9.2.0, “Physical layer procedures (Release 9),”        June 2010

NPL 4

Seigo Nakao, Tomofumi Takata, Daichi Imamura, and Katsuhiko Hiramatsu,“Performance enhancement of E-UTRA uplink control channel in fast fadingenvironments,” Proceeding of IEEE VTC 2009 spring, April 2009

NPL 5

Ericsson and ST-Ericsson, “A/N transmission in the uplink for carrieraggregation,” R1-100909, 3GPP TSG-RAN WG1 #60, February 2010

NPL6

-   -   ZTE, 3GPP RAN1 meeting #57, R1-091702, “Uplink Control Channel        Design for LTE-Advanced,” May 2009

NPL 7

-   -   Panasonic, 3GPP RAN1 meeting #57, R1-091744, “UL ACK/NACK        transmission on PUCCH for Carrier aggregation,” May 2009

NPL 8

-   -   Samsung, CATT, ETRI, Panasonic, Ericsson, ST-Ericsson,        LG-Ericsson, LG Electronics, InterDigital, MediaTek, Huawei, NTT        DOCOMO, Potevio, Alcatel-Lucent, Alcatel-Lucent Shanghai Bell,        RIM, and Sharp, 3GPP RAN1 meeting #62, R1-105040, “Way Forward        on PUCCH Resource Allocation,” August 2010

NPL 9

-   -   CATT, CATR, and CMCC, 3GPP RAN1 meeting #63, R1-106495, “Way        forward on TDD ACK/NAK in Rel-10,” November 2010

NPL 10

NTT DOCOMO, 3GPP RAN1 meeting #63, R1-106175, “Remaining Issue forChannel Selection,” November 2010

BRIEF SUMMARY Technical Problem

In the case where the number of CCs configured (semi-staticallyconfigured) in the terminal is 2, the number of ACK/NACK bits that theterminal reports to the base station is determined on the basis of thenumber of code words (CWs) set in advance in the terminal, i.e., on thebasis of the transmission mode, to be more precise, instead of thenumber of actually transmitted CWs. That is, a mapping table is selectedon the basis of the set transmission mode. For example, when theterminal is configured with 2 CCs and a transmission mode that supportsup to 2 TBs (transmission mode 3, 4, or 8) for PCell and a transmissionmode that supports only 1 TB (transmission mode 1, 2, 5, 6, or 7) forSCell, the terminal reports response signals to the base station using athree-bit mapping table, regardless of the number of actuallytransmitted (dynamic) TBs.

Let us suppose a situation where SPS transmission is performed on PCellwhen a terminal is configured with 2 CCs and a transmission mode thatsupports up to 2 TBs (transmission mode 3, 4, or 8) for PCell and atransmission mode that supports only 1 TB (transmission mode 1, 2, 5, 6,or 7) for SCell. According to the methods disclosed in NPL 8 and NPL 9,two PUCCH resources in total are indicated, the resources including onePUCCH resource for SPS in PCell and one PUCCH resource (implicitresource when cross-carrier scheduling from PCell to SCell is configuredor an explicit resource when no cross-carrier scheduling from PCell toSCell is configured) in SCell.

As illustrated in FIG. 8, however, three PUCCH resources are required inthe above-described situation, where SPS transmission is performed onPCell when the terminal is configured with 2 CCs and the transmissionmode that supports up to 2 TBs (transmission mode 3, 4, or 8) for PCelland the transmission mode that supports only 1 TB (transmission mode 1,2, 5, 6, or 7) for SCell, on the assumption that response signals (thatis, “A, N/D, A”, “N/D, N/D, A”, “A, N/D, N/D”, and “N/D, N/D, N/D”) inportions other than the shaded portions, in which PDSCH (CW1) in PCellis always NACK or DTX, are reported to the base station. That is, onePUCCH resource is lacking.

As disclosed in NPL 8, there is a method using an implicit resourceassociated in a one-to-one correspondence with the top CCE index of theCCEs occupied by a PDCCH indicating a PDSCH in PCell. However, sincethere is no PDCCH intended for the target terminal and indicating aPDSCH scheduled by SPS in PCell, the implicit resource cannot be used.

Such a method as illustrated in FIG. 9, which is obtained by expanding3GPP LTE, may be used. This method uses a PUCCH resource correspondingto one of four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ) (first to fourthPUCCH resource indexes) that are set in advance in a one-to-onecorrespondence with (two-bit) values of a PUCCH transmission powercontrol (TPC) command included in the PDCCH indicating the activation ofSPS; and further uses a PUCCH resource corresponding to one of fourPUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ′ (n⁽¹⁾ ^(PUCCH) ′≠n⁽¹⁾ ^(PUCCH))) (fifth to eighth PUCCH resource indexes), independently of the above.However, according to this method, the amount of signaling from the basestation doubles from four PUCCH resources to eight PUCCH resources. Morespecifically, a condition for the first to fourth PUCCH resource indexesto be used in the terminal is “during SPS,” whereas a condition for thefifth to eighth PUCCH resource indexes to be used in the terminal is“during SPS and when a transmission mode that supports up to 2 TBs isset for PCell,” that is, these conditions are different. Accordingly,there arises a problem in that the amount of signaling needs to beincreased for the latter condition, “during SPS and when a transmissionmode that supports up to 2 TBs is set for PCell,” which occurs lessfrequently.

There is a similar problem when the terminal is configured with 2 CCsand a transmission mode that supports up to 2 TBs (transmission mode 3,4, or 8) for each of PCell and SCell. When SPS transmission is performedon PCell, three PUCCH resources in total are indicated according to themethods disclosed in NPL 8 and NPL 9. The three PUCCH resources are onePUCCH resource for SPS in PCell and two PUCCH resources (implicitresources when cross-carrier scheduling is configured from PCell toSCell or explicit resources when no cross-carrier scheduling from PCellto SCell is configured) in SCell.

As disclosed in NPL 10, let us assume that, when 1 CW (1 TB)transmission is performed on PCell, response signals representing thatPDSCH (CW0) and PDSCH (CW1) in PCell are “ACK, NACK” or “NACK, ACK” arenot used but response signals representing that PDSCH (CW0) and PDSCH(CW1) in PCell are “ACK, ACK” or “NACK, NACK” are used. Under thisassumption, as illustrated in FIG. 10, four PUCCH resources are requiredwhen SPS transmission (1 TB transmission) is performed on PCell in acase where the terminal is configured with 2 CCs and a transmission modethat supports up to 2 TBs (transmission mode 3, 4, or 8) for each ofPCell and SCell. That is, one PUCCH resource is lacking.

In view of the above-mentioned problems, it is an object of the presentinvention to provide a PUCCH resource indicating method capable ofreducing the amount of signaling from a base station and resolving alack of PUCCH resources in PCell during semi-persistent scheduling whena terminal is configured with 2 CCs and a transmission mode thatsupports up to 2 TBs (transmission mode 3, 4, or 8) for at least PCell.

It is an object of the present invention to provide a terminalapparatus, a base station apparatus, a transmitting method, and areceiving method each capable of reducing the amount of signaling from abase station and also resolving a lack of PUCCH resources duringsemi-persistent scheduling in PCell when a terminal is configured with atransmission mode that supports up to 2 TBs for PCell, while ARQ isapplied to communications using an uplink component carrier and aplurality of downlink component carriers associated with the uplinkcomponent carrier.

Solution to Problem

A terminal apparatus according to one aspect of the present inventioncommunicates with a base station using a component carrier groupincluding two downlink component carriers and at least one uplinkcomponent carrier, and is configured with a transmission mode thatsupports up to two TBs for data assigned to at least PCell. The terminalapparatus includes: a control information receiving section thatreceives downlink assignment control information transmitted through adownlink control channel of at least one of the downlink componentcarriers in the component carrier group; a downlink data receivingsection that receives downlink data transmitted through a downlink datachannel indicated by the downlink assignment control information; anerror detecting section that detects a reception error in the downlinkdata; a first response controlling section that transmits a responsesignal through an uplink control channel of the uplink componentcarrier, on a basis of a result of error detection obtained by the errordetecting section and a transmission rule table for the response signal;and a second response controlling section that selects, duringsemi-persistent scheduling, a first uplink control channel from amongthe uplink control channels, on a basis of a first uplink controlchannel index associated in a one-to-one correspondence with firsttransmission power control information included in downlink assignmentcontrol information indicating activate of semi-persistent scheduling.The second response controlling section selects a second uplink controlchannel on a basis of the first uplink control channel.

A base station apparatus according to one aspect of the presentinvention communicates with a terminal apparatus using a componentcarrier group including two downlink component carriers and at least oneuplink component carrier. The base station apparatus includes: a controlinformation transmitting section that transmits downlink assignmentcontrol information through a downlink control channel of at least onedownlink component carrier in the component carrier group, to theterminal apparatus configured with a transmission mode that supports upto 2 TBs for data assigned to at least PCell; a downlink datatransmitting section that transmits downlink data through a downlinkdata channel indicated by the downlink assignment control information tothe terminal apparatus; a first response receiving section that receivesa response signal transmitted from the terminal apparatus through anuplink control channel of the uplink component carrier; and a secondresponse receiving section that selects, during semi-persistentscheduling, a first uplink control channel from among the uplink controlchannels on a basis of a first uplink control channel index associatedin a one-to-one correspondence with first transmission power controlinformation included in downlink assignment control informationindicating activation of semi-persistent scheduling. The second responsereceiving section selects a second uplink control channel on a basis ofthe first uplink control channel.

A transmitting method according to one aspect of the present inventionincludes: performing communications using a component carrier groupincluding two downlink component carriers and at least one uplinkcomponent carrier; and setting a transmission mode that supports up to 2TBs for data assigned to at least PCell. The transmitting methodincludes: a control information receiving step of receiving downlinkassignment control information transmitted through a downlink controlchannel of at least one of the downlink component carriers in thecomponent carrier group; a downlink data receiving step of receivingdownlink data transmitted through a downlink data channel indicated bythe downlink assignment control information; an error detecting step ofdetecting a reception error in the downlink data; a first responsecontrolling step of transmitting a response signal through an uplinkcontrol channel of the uplink component carrier, on a basis of a resultof error detection obtained in the error detecting step and atransmission rule table for the response signal; and a second responsecontrolling step of selecting, during semi-persistent scheduling, afirst uplink control channel from among the uplink control channels on abasis of a first uplink control channel index associated in a one-to-onecorrespondence with first transmission power control informationincluded in downlink assignment control information indicatingactivation of semi-persistent scheduling. The second responsecontrolling step includes selecting a second uplink control channel on abasis of the first uplink control channel.

A receiving method according to one aspect of the present inventionincludes: performing communications using a component carrier groupincluding two downlink component carriers and at least one uplinkcomponent carrier; and setting a transmission mode that supports up to 2TBs for data assigned to at least PCell. The receiving method includes:a control information transmitting step of transmitting downlinkassignment control information through a downlink control channel of atleast one of the downlink component carriers in the component carriergroup; a downlink data transmitting step of transmitting downlink datathrough a downlink data channel indicated by the downlink assignmentcontrol information; a first response receiving step of receiving aresponse signal transmitted from a terminal apparatus through an uplinkcontrol channel of the uplink component carrier; and a second responsereceiving step of selecting, during semi-persistent scheduling, a firstuplink control channel from among the uplink control channels on a basisof a first uplink control channel index associated in a one-to-onecorrespondence with first transmission power control informationincluded in downlink assignment control information indicatingactivation of semi-persistent scheduling. The second response receivingstep includes selecting a second uplink control channel on a basis ofthe first uplink control channel.

Advantageous Effects of Invention

According to the present invention, the amount of signaling from a basestation can be reduced while a lack of PUCCH resources can be resolvedduring semi-persistent scheduling in PCell when a terminal is configuredwith the transmission mode that supports up to 2 TBs for PCell, whileARQ is applied to communications using an uplink component carrier and aplurality of downlink component carriers associated with the uplinkcomponent carrier.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating a method of spreading response signalsand reference signals;

FIG. 2 is a diagram illustrating an operation related to a case whereTDM is applied to response signals and uplink data on PUSCH resources;

FIGS. 3A-3B are diagrams provided for describing asymmetric carrieraggregation and a control sequence applied to individual terminals;

FIG. 4 is a diagram provided for describing asymmetric carrieraggregation and a control sequence applied to individual terminals;

FIG. 5 is diagram 1 provided for describing examples of ACK/NACK mapping(Example 1);

FIG. 6 is diagram 2 provided for describing examples of ACK/NACK mapping(Example 2);

FIG. 7 illustrates an ACK/NACK mapping table;

FIG. 8 is provided for describing a PUCCH resource indicating method(diagram 1);

FIG. 9 is provided for describing a PUCCH resource indicating method forSPS that can be conceived of by a person skilled in the art;

FIG. 10 is provided for describing a PUCCH resource indicating method(diagram 2);

FIG. 11 is a block diagram illustrating a main configuration of a basestation according to an embodiment of the present invention;

FIG. 12 is a block diagram illustrating a main configuration of aterminal according to the embodiment of the present invention;

FIG. 13 is a block diagram illustrating a configuration of the basestation according to the embodiment of the present invention;

FIG. 14 is a block diagram illustrating a configuration of the terminalaccording to the embodiment of the present invention;

FIG. 15 illustrates a control example for PUCCH resources according tothe embodiment of the present invention (example 1);

FIG. 16 illustrates a control example for PUCCH resources according tothe embodiment of the present invention (example 2);

FIG. 17 illustrates a first PUCCH resource indicating method for SPSaccording to the embodiment of the present invention;

FIG. 18 illustrates a second PUCCH resource indicating method for SPSaccording to the embodiment of the present invention (method 1); and

FIG. 19 illustrates a second PUCCH resource indicating method for SPSaccording to the embodiment of the present invention (method 2).

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. Throughout theembodiments, the same elements are assigned the same reference numeralsand any duplicate description of the elements is omitted.

Embodiment 1

FIG. 11 is a main configuration diagram of base station 100 according tothe present embodiment. Base station 100 communicates with terminal 200using a component carrier group including two downlink componentcarriers and at least one uplink component carrier. In base station 100,mapping section 108 maps, for terminal 200 configured with thetransmission mode that supports up to 2 transport blocks for dataassigned to at least a first downlink component carrier (PCell) of thetwo downlink component carriers, downlink assignment control information(DCI) to a downlink control channel (PDCCH) of at least one downlinkcomponent carrier in the component carrier group, and also maps downlinkdata to a downlink data channel (PDSCH) indicated by the downlinkassignment control information. As a result, the downlink assignmentcontrol information is transmitted through the downlink control channel(PDCCH), and the downlink data is transmitted through the downlink datachannel (PDSCH). Further, PUCCH extracting section 114 receives aresponse signal corresponding to the downlink data through an uplinkcontrol channel (PUCCH) of the uplink component carrier. During SPS,PUCCH extracting section 114 selects a first uplink control channelresource corresponding to a first index of indexes (PUCCH resourceindexes) indicating uplink control channel resources (PUCCH resources)included in the uplink control channel (PUCCH), and selects a seconduplink control channel resource on the basis of the first uplink controlchannel resource.

FIG. 12 is a main configuration diagram of terminal 200 according to thepresent embodiment. Terminal 200 communicates with base station 100using a component carrier group including two downlink componentcarriers and at least one uplink component carrier. Terminal 200 isconfigured with the transmission mode that supports up to 2 transportblocks for data assigned to at least a first downlink component carrier(PCell) of the two downlink component carriers. In terminal 200,extraction section 204 receives downlink assignment control information(DCI) transmitted through a downlink control channel (PDCCH) of at leastone downlink component carrier in the component carrier group, andreceives downlink data transmitted through a downlink data channel(PDSCH) indicated by the downlink assignment control information. CRCsection 211 detects a reception error of the downlink data. Controlsection 208 transmits a response signal corresponding to the downlinkdata through an uplink control channel (PUCCH) of the uplink componentcarrier, on the basis of the result of error detection obtained by CRCsection 211 and a transmission rule table for the response signal.During semi-persistent scheduling (SPS), control section 208 selects afirst uplink control channel resource corresponding to a first index ofindexes (PUCCH resource indexes) indicating uplink control channelresources (PUCCH resources) included in the uplink control channel, andselects a second uplink control channel resource on the basis of theselected first uplink control channel resource.

Resources for transmission of response signals including the firstuplink control channel resource and the second uplink control channelresource are set in the transmission rule table for terminal 200configured with the first downlink component carrier. Furthermore, thefirst index is defined as a PUCCH resource index that is associated in aone-to-one correspondence with first transmission power controlinformation (TPC command for PUCCH) included in the downlink assignmentcontrol indicating the activation of SPS.

(Configuration of Base Station)

FIG. 13 is a configuration diagram of base station 100 according toEmbodiment 1 of the present invention. In FIG. 13, base station 100includes control section 101, control information generating section102, coding section 103, modulation section 104, coding section 105,data transmission controlling section 106, modulation section 107,mapping section 108, inverse fast Fourier transform (IFFT) section 109,CP adding section 110, radio transmitting section 111, radio receivingsection 112, CP removing section 113, PUCCH extracting section 114,despreading section 115, sequence controlling section 116, correlationprocessing section 117, A/N determining section 118, bundled A/Ndespreading section 119, inverse discrete Fourier transform (IDFT)section 120, bundled A/N determining section 121 and retransmissioncontrol signal generating section 122.

Control section 101 assigns a downlink resource for transmitting controlinformation (i.e., downlink control information assignment resource) anda downlink resource for transmitting downlink data (i.e., downlink dataassignment resource) for a resource assignment target terminal(hereinafter, referred to as “destination terminal” or simply“terminal”) 200. This resource assignment is performed in a downlinkcomponent carrier in a component carrier group configured for resourceassignment target terminal 200. In addition, the downlink controlinformation assignment resource is selected from among the resourcescorresponding to downlink control channel (i.e., PDCCH) in each downlinkcomponent carrier. Moreover, the downlink data assignment resource isselected from among the resources corresponding to downlink data channel(i.e., PDSCH) in each downlink component carrier. In addition, whenthere are a plurality of resource assignment target terminals 200,control section 101 assigns different resources to resource assignmenttarget terminals 200, respectively.

The downlink control information assignment resources are equivalent toL1/L2 CCH described above. To put it more specifically, the downlinkcontrol information assignment resources are each formed of one or aplurality of CCEs (or R-CCEs, and may be referred to as “CCE” simply,without any distinction between CCE and R-CCE).

Control section 101 determines the coding rate used for transmittingcontrol information to resource assignment target terminal 200. The datasize of the control information varies depending on the coding rate.Thus, control section 101 assigns a downlink control informationassignment resource having the number of CCEs that allows the controlinformation having this data size to be mapped to the resource.

Control section 101 outputs information on the downlink data assignmentresource to control information generating section 102. Moreover,control section 101 outputs information on the coding rate to codingsection 103. In addition, control section 101 determines and outputs thecoding rate of transmission data (i.e., downlink data) to coding section105. Moreover, control section 101 outputs information on the downlinkdata assignment resource and downlink control information assignmentresource to mapping section 108. However, control section 101 controlsthe assignment in such a way that the downlink data and downlink controlinformation for the downlink data are mapped to the same downlinkcomponent carrier.

Control information generating section 102 generates and outputs controlinformation including the information on the downlink data assignmentresource to coding section 103. This control information is generatedfor each downlink component carrier. In addition, when there are aplurality of resource assignment target terminals 200, the controlinformation includes the terminal ID of each destination terminal 200 inorder to distinguish resource assignment target terminals 200 from oneanother. For example, the control information includes CRC bits maskedby the terminal ID of destination terminal 200. This control informationmay be referred to as “control information carrying downlink assignment”or “downlink control information (DCI).”

Coding section 103 encodes the control information using the coding ratereceived from control section 101 and outputs the coded controlinformation to modulation section 104.

Modulation section 104 modulates the coded control information andoutputs the resultant modulation signals to mapping section 108.

Coding section 105 uses the transmission data (i.e., downlink data) foreach destination terminal 200 and the coding rate information fromcontrol section 101 as input and encodes and outputs the transmissiondata to data transmission controlling section 106. However, when aplurality of downlink component carriers are assigned to destinationterminal 200, coding section 105 encodes each piece of transmission datato be transmitted on a corresponding one of the downlink componentcarriers and transmits the coded pieces of transmission data to datatransmission controlling section 106.

Data transmission controlling section 106 outputs the coded transmissiondata to modulation section 107 and also keeps the coded transmissiondata at the initial transmission. Data transmission controlling section106 keeps the coded transmission data for each destination terminal 200.In addition, data transmission controlling section 106 keeps thetransmission data for one destination terminal 200 for each downlinkcomponent carrier on which the transmission data is transmitted. Thus,it is possible to perform not only retransmission control for overalldata transmitted to destination terminal 200, but also retransmissioncontrol for data on each downlink component carrier.

Furthermore, upon reception of a NACK or DTX for downlink datatransmitted on a certain downlink component carrier from retransmissioncontrol signal generating section 122, data transmission controllingsection 106 outputs the data kept in the manner described above andcorresponding to this downlink component carrier to modulation section107. Upon reception of an ACK for the downlink data transmitted on acertain downlink component carrier from retransmission control signalgenerating section 122, data transmission controlling section 106deletes the data kept in the manner described above and corresponding tothis downlink component carrier.

Modulation section 107 modulates the coded transmission data receivedfrom data transmission controlling section 106 and outputs the resultantmodulation signals to mapping section 108.

Mapping section 108 maps the modulation signals of the controlinformation received from modulation section 104 to the resourceindicated by the downlink control information assignment resourcereceived from control section 101 and outputs the resultant modulationsignals to IFFT section 109.

Mapping section 108 maps the modulation signals of the transmission datareceived from modulation section 107 to the resource (i.e., PDSCH (i.e.,downlink data channel)) indicated by the downlink data assignmentresource received from control section 101 (i.e., information includedin the control information) and outputs the resultant modulation signalsto IFFT section 109.

The control information and transmission data mapped to a plurality ofsubcarriers in a plurality of downlink component carriers in mappingsection 108 is transformed into time-domain signals fromfrequency-domain signals in IFFT section 109, and CP adding section 110adds a CP to the time-domain signals to form OFDM signals. The OFDMsignals undergo transmission processing such as digital to analog (D/A)conversion, amplification and up-conversion and/or the like in radiotransmitting section 111 and are transmitted to terminal 200 via anantenna.

Radio receiving section 112 receives, via an antenna, the uplinkresponse signals or reference signals transmitted from terminal 200, andperforms reception processing such as down-conversion, A/D conversionand/or the like on the uplink response signals or reference signals.

CP removing section 113 removes the CP added to the uplink responsesignals or reference signals from the uplink response signals orreference signals that have undergone the reception processing.

PUCCH extracting section 114 extracts, from the PUCCH signals includedin the received signals, the signals in the PUCCH region correspondingto the bundled ACK/NACK resource previously indicated to terminal 200.The bundled ACK/NACK resource herein refers to a resource used fortransmission of the bundled ACK/NACK signals and adopting the DFT-S-OFDMformat structure. To put it more specifically, PUCCH extracting section114 extracts the data part of the PUCCH region corresponding to thebundled ACK/NACK resource (i.e., SC-FDMA symbols on which the bundledACK/NACK resource is assigned) and the reference signal part of thePUCCH region (i.e., SC-FDMA symbols on which the reference signals fordemodulating the bundled ACK/NACK signals are assigned). PUCCHextracting section 114 outputs the extracted data part to bundled A/Ndespreading section 119 and outputs the reference signal part todespreading section 115-1.

In addition, PUCCH extracting section 114 extracts, from the PUCCHsignals included in the received signals, a plurality of PUCCH regionscorresponding to an A/N resource associated with a CCE that has beenoccupied by the PDCCH used for transmission of the downlink assignmentcontrol information (DCI), and corresponding to a plurality of A/Nresources previously indicated to terminal 200. The A/N resource hereinrefers to the resource to be used for transmission of an A/N. To put itmore specifically, PUCCH extracting section 114 extracts the data partof the PUCCH region corresponding to the A/N resource (i.e., SC-FDMAsymbols on which the uplink control signals are assigned) and thereference signal part of the PUCCH region (i.e., SC-FDMA symbols onwhich the reference signals for demodulating the uplink control signalsare assigned). PUCCH extracting section 114 outputs both of theextracted data part and reference signal part to despreading section115-2. In this manner, the response signals are received on the resourceselected from the PUCCH resource associated with the CCE and thespecific PUCCH resource previously indicated to terminal 200. The PUCCHresource selected by PUCCH extracting section 114 will be describedhereinafter in detail.

Sequence controlling section 116 generates a base sequence that may beused for spreading each of the A/N reported from terminal 200, thereference signals for the A/N, and the reference signals for the bundledACK/NACK signals (i.e., length-12 ZAC sequence). In addition, sequencecontrolling section 116 identifies a correlation window corresponding toa resource on which the reference signals may be assigned (hereinafter,referred to as “reference signal resource”) in PUCCH resources that maybe used by terminal 200. Sequence controlling section 116 outputs theinformation indicating the correlation window corresponding to thereference signal resource on which the reference signals may be assignedin bundled ACK/NACK resources and the base sequence to correlationprocessing section 117-1. Sequence controlling section 116 outputs theinformation indicating the correlation window corresponding to thereference signal resource and the base sequence to correlationprocessing section 117-1. In addition, sequence controlling section 116outputs the information indicating the correlation window correspondingto the A/N resources on which an A/N and the reference signals for theA/N are assigned and the base sequence to correlation processing section117-2.

Despreading section 115-1 and correlation processing section 117-1perform processing on the reference signals extracted from the PUCCHregion corresponding to the bundled ACK/NACK resource.

To put it more specifically, despreading section 115-1 despreads thereference signal part using a Walsh sequence to be used insecondary-spreading for the reference signals of the bundled ACK/NACKresource by terminal 200 and outputs the despread signals to correlationprocessing section 117-1.

Correlation processing section 117-1 uses the information indicating thecorrelation window corresponding to the reference signal resource andthe base sequence and thereby finds a correlation value between thesignals received from despreading section 115-1 and the base sequencethat may be used in primary-spreading in terminal 200. Correlationprocessing section 117-1 outputs the correlation value to bundled A/Ndetermining section 121.

Despreading section 115-2 and correlation processing section 117-2perform processing on the reference signals and A/Ns extracted from theplurality of PUCCH regions corresponding to the plurality of A/Nresources.

To put it more specifically, despreading section 115-2 despreads thedata part and reference signal part using a Walsh sequence and a DFTsequence to be used in secondary-spreading for the data part andreference signal part of each of the A/N resources by terminal 200, andoutputs the despread signals to correlation processing section 117-2.

Correlation processing section 117-2 uses the information indicating thecorrelation window corresponding to each of the A/N resources and thebase sequence and thereby finds a correlation value between the signalsreceived from despreading section 115-2 and a base sequence that may beused in primary-spreading by terminal 200. Correlation processingsection 117-2 outputs each correlation value to A/N determining section118.

A/N determining section 118 determines, on the basis of the plurality ofcorrelation values received from correlation processing section 117-2,which of the A/N resources is used to transmit the signals from terminal200 or none of the A/N resources is used. When determining that thesignals are transmitted using one of the A/N resources from terminal200, A/N determining section 118 performs coherent detection using acomponent corresponding to the reference signals and a componentcorresponding to the A/N and outputs the result of coherent detection toretransmission control signal generating section 122. Meanwhile, whendetermining that terminal 200 uses none of the A/N resources, A/Ndetermining section 118 outputs the determination result indicating thatnone of the A/N resources is used to retransmission control signalgenerating section 122.

Bundled A/N despreading section 119 despreads, using a DFT sequence, thebundled ACK/NACK signals corresponding to the data part of the bundledACK/NACK resource received from PUCCH extracting section 114 and outputsthe despread signals to IDFT section 120.

IDFT section 120 transforms the bundled ACK/NACK signals in thefrequency-domain received from bundled A/N despreading section 119 intotime-domain signals by IDFT processing and outputs the bundled ACK/NACKsignals in the time-domain to bundled A/N determining section 121.

Bundled A/N determining section 121 demodulates the bundled ACK/NACKsignals corresponding to the data part of the bundled ACK/NACK resourcereceived from IDFT section 120, using the reference signal informationon the bundled ACK/NACK signals that is received from correlationprocessing section 117-1. In addition, bundled A/N determining section121 decodes the demodulated bundled ACK/NACK signals and outputs theresult of decoding to retransmission control signal generating section122 as the bundled A/N information. However, when the correlation valuereceived from correlation processing section 117-1 is smaller than athreshold, and bundled A/N determining section 121 thus determines thatterminal 200 does not use any bundled A/N resource to transmit thesignals, bundled A/N determining section 121 outputs the result ofdetermination to retransmission control signal generating section 122.

Retransmission control signal generating section 122 determines whetheror not to retransmit the data transmitted on the downlink componentcarrier (i.e., downlink data) on the basis of the information receivedfrom bundled A/N determining section 121 and the information receivedfrom A/N determining section 118 and generates retransmission controlsignals based on the result of determination. To put it morespecifically, when determining that downlink data transmitted on acertain downlink component carrier needs to be retransmitted,retransmission control signal generating section 122 generatesretransmission control signals indicating a retransmission command forthe downlink data and outputs the retransmission control signals to datatransmission controlling section 106. In addition, when determining thatthe downlink data transmitted on a certain downlink component carrierdoes not need to be retransmitted, retransmission control signalgenerating section 122 generates retransmission control signalsindicating not to retransmit the downlink data transmitted on thedownlink component carrier and outputs the retransmission controlsignals to data transmission controlling section 106.

(Configuration of Terminal)

FIG. 14 is a block diagram illustrating a configuration of terminal 200according to Embodiment 1. In FIG. 14, terminal 200 includes radioreceiving section 201, CP removing section 202, fast Fourier transform(FFT) section 203, extraction section 204, demodulation section 205,decoding section 206, determination section 207, control section 208,demodulation section 209, decoding section 210, CRC section 211,response signal generating section 212, coding and modulation section213, primary-spreading sections 214-1 and 214-2, secondary-spreadingsections 215-1 and 215-2, DFT section 216, spreading section 217, IFFTsections 218-1, 218-2 and 218-3, CP adding sections 219-1, 219-2 and219-3, time-multiplexing section 220, selection section 221 and radiotransmitting section 222.

Radio receiving section 201 receives, via an antenna, OFDM signalstransmitted from base station 100 and performs reception processing suchas down-conversion, ND conversion and/or the like on the received OFDMsignals. It should be noted that, the received OFDM signals includePDSCH signals assigned to a resource in a PDSCH (i.e., downlink data),or PDCCH signals assigned to a resource in a PDCCH.

CP removing section 202 removes a CP that has been added to the OFDMsignals from the OFDM signals that have undergone the receptionprocessing.

FFT section 203 transforms the received OFDM signals intofrequency-domain signals by FFT processing and outputs the resultantreceived signals to extraction section 204.

Extraction section 204 extracts, from the received signals to bereceived from FFT section 203, downlink control channel signals (i.e.,PDCCH signals) in accordance with coding rate information to bereceived. To put it more specifically, the number of CCEs (or R-CCEs)forming a downlink control information assignment resource variesdepending on the coding rate. Thus, extraction section 204 uses thenumber of CCEs that corresponds to the coding rate as units ofextraction processing, and extracts downlink control channel signals. Inaddition, the downlink control channel signals are extracted for eachdownlink component carrier. The extracted downlink control channelsignals are outputted to demodulation section 205.

Extraction section 204 extracts downlink data (i.e., downlink datachannel signals (i.e., PDSCH signals)) from the received signals on thebasis of information on the downlink data assignment resource intendedfor terminal 200 to be received from determination section 207 to bedescribed, hereinafter, and outputs the downlink data to demodulationsection 209. As described above, extraction section 204 receives thedownlink assignment control information (i.e., DCI) mapped to the PDCCHand receives the downlink data on the PDSCH.

Demodulation section 205 demodulates the downlink control channelsignals received from extraction section 204 and outputs the obtainedresult of demodulation to decoding section 206.

Decoding section 206 decodes the result of demodulation received fromdemodulation section 205 in accordance with the received coding rateinformation and outputs the obtained result of decoding to determinationsection 207.

Determination section 207 performs blind-determination (i.e.,monitoring) to find out whether or not the control information includedin the result of decoding received from decoding section 206 is thecontrol information intended for terminal 200. This determination ismade in units of decoding results corresponding to the units ofextraction processing. For example, determination section 207 demasksthe CRC bits by the terminal ID of terminal 200 and determines that thecontrol information resulted in CRC=OK (no error) as the controlinformation intended for terminal 200. Determination section 207 outputsinformation on the downlink data assignment resource intended forterminal 200, which is included in the control information intended forterminal 200, to extraction section 204.

In addition, when detecting the control information (i.e., downlinkassignment control information) intended for terminal 200, determinationsection 207 informs control section 208 that ACK/NACK signals will begenerated (or are present). Moreover, when detecting the controlinformation intended for terminal 200 from PDCCH signals, determinationsection 207 outputs information on a CCE that has been occupied by thePDCCH to control section 208.

Control section 208 identifies the A/N resource associated with the CCEon the basis of the information on the CCE received from determinationsection 207. Control section 208 outputs, to primary-spreading section214-1, a base sequence and a cyclic shift value corresponding to the A/Nresource associated with the CCE or the A/N resource previouslyindicated by base station 100, and also outputs a Walsh sequence and aDFT sequence corresponding to the A/N resource to secondary-spreadingsection 215-1. In addition, control section 208 outputs the frequencyresource information on the A/N resource to IFFT section 218-1.

When determining to transmit bundled ACK/NACK signals using a bundledACK/NACK resource, control section 208 outputs the base sequence andcyclic shift value corresponding to the reference signal part (i.e.,reference signal resource) of the bundled ACK/NACK resource previouslyindicated by base station 100 to primary-spreading section 214-2 andoutputs a Walsh sequence to secondary-spreading section 215-2. Inaddition, control section 208 outputs the frequency resource informationon the bundled ACK/NACK resource to IFFT section 218-2.

Control section 208 outputs a DFT sequence used for spreading the datapart of the bundled ACK/NACK resource to spreading section 217 andoutputs the frequency resource information on the bundled ACK/NACKresource to IFFT section 218-3.

Control section 208 selects the bundled ACK/NACK resource or the A/Nresource and instructs selection section 221 to output the selectedresource to radio transmitting section 222. Moreover, control section208 instructs response signal generating section 212 to generate thebundled ACK/NACK signals or the ACK/NACK signals in accordance with theselected resource. The method of notifying the A/N resource (i.e., PUCCHresource) in control section 208 will be described in detail,hereinafter.

Demodulation section 209 demodulates the downlink data received fromextraction section 204 and outputs the demodulated downlink data todecoding section 210.

Decoding section 210 decodes the downlink data received fromdemodulation section 209 and outputs the decoded downlink data to CRCsection 211.

CRC section 211 performs error detection on the decoded downlink datareceived from decoding section 210, for each downlink component carrierusing CRC and outputs an ACK when CRC=OK (no error) or outputs a NACKwhen CRC=Not OK (error) to response signal generating section 212.Moreover, CRC section 211 outputs the decoded downlink data as thereceived data when CRC=OK (no error).

Response signal generating section 212 generates response signals on thebasis of the reception condition of downlink data (i.e., result of errordetection on downlink data) on each downlink component carrier receivedfrom CRC section 211. To put it more specifically, when instructed togenerate the bundled ACK/NACK signals from control section 208, responsesignal generating section 212 generates the bundled ACK/NACK signalsincluding the results of error detection for the respective componentcarriers as individual pieces of data. Meanwhile, when instructed togenerate ACK/NACK signals from control section 208, response signalgenerating section 212 generates ACK/NACK signals of one symbol.Response signal generating section 212 outputs the generated responsesignals to coding and modulation section 213.

Upon reception of the bundled ACK/NACK signals, coding and modulationsection 213 encodes and modulates the received bundled ACK/NACK signalsto generate the modulation signals of 12 symbols and outputs themodulation signals to DFT section 216. In addition, upon reception ofthe ACK/NACK signals of one symbol, coding and modulation section 213modulates the ACK/NACK signals and outputs the modulation signals toprimary-spreading section 214-1.

DFT section 216 performs DFT processing on 12 time-series sets ofreceived bundled ACK/NACK signals to obtain 12 signal components in thefrequency-domain. DFT section 216 outputs the 12 signal components tospreading section 217.

Spreading section 217 spreads the 12 signal components received from DFTsection 216 using a DFT sequence indicated by control section 208 andoutputs the spread signal components to IFFT section 218-3.

Primary-spreading sections 214-1 and 214-2 corresponding to the A/Nresource and the reference signal resource of bundled ACK/NACK resourcespread ACK/NACK signals or reference signals using a base sequencecorresponding to the resource in accordance with an instruction fromcontrol section 208 and outputs the spread signals tosecondary-spreading sections 215-1 and 215-2.

Secondary-spreading sections 215-1 and 215-2 spread the receivedprimary-spread signals using a Walsh sequence or a DFT sequence inaccordance with an instruction from control section 208 and outputs thespread signals to IFFT sections 218-1 and 218-2.

IFFT sections 218-1, 218-2 and 218-3 perform IFFT processing on thereceived signals in association with the frequency positions where thesignals are to be allocated, in accordance with an instruction fromcontrol section 208. Accordingly, the signals inputted to IFFT sections218-1, 218-2 and 218-3 (i.e., ACK/NACK signals, the reference signals ofA/N resource, the reference signals of bundled ACK/NACK resource andbundled ACK/NACK signals) are transformed into time-domain signals.

CP adding sections 219-1, 219-2 and 219-3 add the same signals as thelast part of the signals obtained by IFFT processing to the beginning ofthe signals as a CP.

Time-multiplexing section 220 time-multiplexes the bundled ACK/NACKsignals received from CP adding section 219-3 (i.e., signals transmittedusing the data part of the bundled ACK/NACK resource) and the referencesignals of the bundled ACK/NACK resource to be received from CP addingsection 219-2 on the bundled ACK/NACK resource and outputs themultiplexed signals to selection section 221.

Selection section 221 selects one of the bundled ACK/NACK resourcereceived from time-multiplexing section 220 and the A/N resourcereceived from CP adding section 219-1 and outputs the signals assignedto the selected resource to radio transmitting section 222.

Radio transmitting section 222 performs transmission processing such asD/A conversion, amplification and up-conversion and/or the like on thesignals received from selection section 221 and transmits the resultantsignals to base station 100 via an antenna.

(Operations of Base Station 100 and Terminal 200)

A description will be provided regarding operations of base station 100and terminal 200 each configured in the manner described above.

In the following description, terminal 200 is configured with twodownlink component carriers (one PCell and one SCell) and one uplinkcomponent carrier. Furthermore, terminal 200 is configured with atransmission mode that supports up to 2 TBs (transmission mode 3, 4, or8) for data assigned to at least PCell of the two downlink componentcarriers.

Terminal 200 configured in the manner described above is furtherconfigured with a mapping table illustrated in FIG. 8 (in which atransmission mode that supports only 1 TB is set for SCell) or a mappingtable illustrated in FIG. 10 (in which the transmission mode thatsupports up to 2 TBs is set for SCell). Resources for transmission ofresponse signals including PUCCH resources 1 to 3 (in the case of FIG.8) or PUCCH resources 1 to 4 are set in the mapping table (FIG. 8 orFIG. 10) for terminal 200 configured in the manner described above.

First, a PUCCH resource indicating method during dynamic scheduling interminal 200 configured in the manner described above will be describedin detail with reference to FIG. 15.

FIG. 15 illustrates an example of cross-carrier scheduling from PCell(downlink component carrier 1) to SCell (downlink component carrier 2).That is, in FIG. 15, a PDCCH in PCell indicates a PDSCH in SCell.

Terminal 200 (control section 208) transmits a response signalcorresponding to downlink data through a PUCCH (PUCCH resource) of theuplink component carrier on the basis of a result of error detectionobtained by CRC section 211 and a mapping table (transmission ruletable) for the response signal.

For example, in FIG. 15, it is assumed that the top CCE index of theCCEs occupied by the PDCCH indicating the PDSCH in PCell is n_CCE. Inthis case, PUCCH resource 1 in the uplink component carrier is assignedin association in a one-to-one correspondence with the top CCE index(n_CCE) (implicit signaling). Furthermore, PUCCH resource 2 in theuplink component carrier is assigned in association in a one-to-onecorrespondence with the next index (n_CCE+1) of the top CCE index(n_CCE) of the CCEs occupied by the PDCCH indicating the PDSCH in PCell(implicit signaling).

Similarly, in FIG. 15, it is assumed that the top CCE index of the CCEsoccupied by the PDCCH in PCell that indicates the PDSCH in SCell forwhich cross-carrier scheduling from PCell to SCell is configured isn_CCE′(n_CCE′≠n_CCE). In this case, PUCCH resource 3 in the uplinkcomponent carrier is assigned in association in a one-to-onecorrespondence with the top CCE index (n_CCE′) (implicit signaling).Furthermore, for terminal 200 configured with a transmission mode thatsupports up to 2 TBs (transmission mode 3, 4, or 8) for data assigned toSCell, PUCCH resource 4 in the uplink component carrier is assigned inassociation in a one-to-one correspondence with the next index(n_CCE′+1) of the top CCE index (n_CCE′) of the CCEs occupied by thePDCCH indicating the PDSCH in SCell (implicit signaling).

During dynamic scheduling, similarly to terminal 200, base station 100(PUCCH extracting section 114) selects a recourse used for responsesignal transmission, from among the PUCCH resources associated with theCCEs occupied by the PDCCH indicated to terminal 200.

Note that the resource indicating method described above is an examplein which all the PUCCH resources are implicitly signaled, but thepresent invention is not limited to this example. For example, all thePUCCH resources may be explicitly signaled. Alternatively, some of thePUCCH resources (for example, PUCCH resource 1 as well as PUCCH resource3 during cross-carrier scheduling, which are illustrated in FIG. 15) maybe implicitly signaled, and the other PUCCH resources (for example,PUCCH resource 2 and PUCCH resource 4 as well as PUCCH resource 3 duringnon-cross-carrier scheduling) may be explicitly signaled.

Hereinabove, the PUCCH resource indicating method used during dynamicscheduling has been described.

Next, a PUCCH resource indicating method used during semi-persistentscheduling (SPS) in terminal 200 configured as described above will bedescribed in detail with reference to FIG. 16, FIG. 17, and FIG. 18.

FIG. 16 illustrates an example in which cross-carrier scheduling isconfigured from PCell (downlink component carrier 1) to SCell (downlinkcomponent carrier 2). That is, in FIG. 16, PDCCH in PCell indicatesPDSCH in SCell.

Terminal 200 (control section 208) transmits a response signalcorresponding to downlink data through a PUCCH (PUCCH resource) of theuplink component carrier on the basis of a result of error detectionobtained by CRC section 211 and a mapping table (transmission ruletable) for the response signal.

Once SPS is activated, there is no PDCCH indicating a PDSCH for SPS inPCell. For this reason, once SPS activation is activated, PUCCH resource1 and PUCCH resource 2 (implicit resources; see, for example, FIG. 15)in the uplink component carrier, which are associated in a one-to-onecorrespondence with the CCE indexes (for example, n_CCE and n_CCE+1),cannot be assigned for terminal 200.

Accordingly, during SPS, terminal 200 (control section 208) firstselects, as PUCCH resource 1, a resource corresponding to the PUCCHresource index in association in a one-to-one correspondence with thetransmission power control information (TPC command for PUCCH) includedin the downlink assignment control information indicating the activationof SPS, from among the PUCCH resource indexes indicating the PUCCHresources included in the PUCCH.

FIG. 17 illustrates a correspondence between the transmission powercontrol information (TPC command for PUCCH) included in PDCCH on whichthe SPS activation is indicated to terminal 200 and four PUCCH resourceindexes (n⁽¹⁾ ^(PUCCH) ) set in advance by base station 100. That is,each value (‘00’ to ‘11’) of the TPC command for PUCCH is used as anindex indicating any of values of the four PUCCH resources (first tofourth PUCCH resource indexes) set in advance by base station 100. Notethat FIG. 17 is the same as a correspondence illustrated in an upperportion of FIG. 9, that is, a correspondence used in LTE (Release 8).

For example, with regard to PUCCH resource 1, terminal 200 selects onePUCCH resource index from among the four PUCCH resource indexes (n⁽¹⁾^(PUCCH) ) on the basis of the value of the TPC command for PUCCH (thetransmission power control information included in PDCCH on which theSPS activation is indicated) illustrated in FIG. 17. Then, a resourcecorresponding to the selected PUCCH resource index is assigned as PUCCHresource 1 in the uplink component carrier.

Subsequently, with regard to PUCCH resource 2, terminal 200 selects onePUCCH resource on the basis of a correspondence (illustrated in FIG. 18)between the values of the TPC command for PUCCH and the four PUCCHresource indexes. In FIG. 18, the values of the TPC command for PUCCHare respectively associated with values (n⁽¹⁾ ^(PUCCH) +1) obtained byadding 1 to the four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ) illustratedin FIG. 17. Then, a resource corresponding to the selected PUCCHresource index is assigned as PUCCH resource 2 in the uplink componentcarrier.

That is, terminal 200 (control section 208) selects PUCCH resource 2 onthe basis of the PUCCH resource index of PUCCH resource 1 selected withreference to FIG. 17. Specifically, as illustrated in FIG. 18, terminal200 selects, as PUCCH resource 2, a resource corresponding to a value(PUCCH resource index) obtained by adding 1 to the PUCCH resource indexof PUCCH resource 1.

For example, a description will be given regarding the case where theTPC command for PUCCH included in the PDCCH that is indicated toterminal 200 for activation of SPS is ‘01.’ In this case, with referenceto FIG. 17, terminal 200 selects, as PUCCH resource 1, a resource(second PUCCH resource index) corresponding to the TPC command for PUCCH‘01’ from among the four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ). Withreference to FIG. 18, terminal 200 further selects, as PUCCH resource 2,a resource (a value obtained by adding 1 to the second PUCCH resourceindex) corresponding to the TPC command for PUCCH ‘01’ from among thefour PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) +1). The same applies to thecase where the TPC command for PUCCH included in the PDCCH indicated toterminal 200 is other than ‘01’ (‘00,’ ‘10,’ ‘11’).

Meanwhile, in FIG. 16, it is assumed that the top CCE index of the CCEsoccupied by the PDCCH in PCell that indicates the PDSCH in SCellconfigured with cross-carrier scheduling from PCell to SCell isn_CCE′(n_CCE′≠n_CCE) similarly to FIG. 15.

In this case, similarly to FIG. 15 (during dynamic scheduling), PUCCHresource 3 in the uplink component carrier is assigned in association ina one-to-one correspondence with the top CCE index (n_CCE′) (implicitsignaling). When terminal 200 is configured with a transmission modethat supports up to 2 TBs (transmission mode 3, 4, or 8) for SCell,PUCCH resource 4 in the uplink component carrier is further assigned inassociation in a one-to-one correspondence with the next index(n_CCE′+1) of the top CCE index (n_CCE′) of the CCEs occupied by thePDCCH indicating the PDSCH in SCell (implicit signaling).

During SPS, base station 100 (PUCCH extracting section 114) selects arecourse used for response signal transmission, from among specificPUCCH resources indicated in advance to terminal 200 or the PUCCHresources associated with the CCEs occupied by the PDCCH indicated toterminal 200. On this occasion, for terminal 200 configured with atransmission mode that supports up to 2 TBs for at least PCell, basestation 100 selects the second resource for SPS on the basis of thePUCCH resource index used for selection of the first resource for SPS(the PUCCH resource index associated with the TPC command for PUCCH).

Hereinabove, the PUCCH resource indicating method used during SPS hasbeen described.

In this way, during dynamic scheduling or semi-persistent scheduling(SPS), terminal 200 selects a resource used for response signaltransmission, from among the PUCCH resources associated with the CCEsoccupied by the PDCCH indicated to terminal 200 or specific PUCCHresources indicated in advance by base station 100 and controls theresponse signal transmission.

For example, when terminal 200 is configured with a transmission modethat supports up to 2 TBs for PCell, during dynamic scheduling, terminal200 transmits the response signal using: a PUCCH resource (implicitresource) associated with the top CCE index of the CCEs occupied by thePDCCH indicating each of the PDSCH in PCell and PDSCH in SCell; and aPUCCH resource (implicit resource) associated with the next CCE index ofthe top CCE index. Specifically, during dynamic scheduling, a valueassociated with the top CCE index (n_CCE) of the CCEs used for PDCCHtransmission is used as the PUCCH resource index (the value of n⁽¹⁾^(PUCCH) ) (see, for example, FIG. 15). Furthermore, when a transmissionmode that supports up to 2 TBs is set for PCell, a value associated withn_CCE+1 is used as the PUCCH resource index.

Meanwhile, during SPS in PCell, terminal 200 uses, for PCell: a PUCCHresource (explicit resource) that is associated in a one-to-onecorrespondence with the (two-bit) value of the TPC command for PUCCHindicated when SPS is activated; and a resource (obtained by adding 1 tothe index) adjacent to the PUCCH resource (explicit resource).

That is, terminal 200 selects the second resource for SPS on the basisof the first resource for SPS selected in accordance with the TPCcommand for PUCCH. Specifically, terminal 200 selects the secondresource for SPS (n⁽¹⁾ ^(PUCCH) +1) using the PUCCH resource index (n⁽¹⁾^(PUCCH) ) used for selection of the first resource for SPS. That is,during SPS, the PUCCH resource index (the value of n⁽¹⁾ ^(PUCCH) ) isdetermined in accordance with settings made by base station 100 (see,for example, FIG. 17). Furthermore, when a transmission mode thatsupports up to 2 TBs is set for PCell, the PUCCH resource index is givenas n⁽¹⁾ ^(PUCCH) +1.

As a result, when configured with a transmission mode that supports upto 2 TBs (that is, 2 code words) (for example, MIMO transmission mode)for data assigned to at least PCell, even during SPS, terminal 200 canidentify all PUCCH resources used for response signal transmission. Inother words, it is possible for terminal 200 to prevent a problem inthat PUCCH resources cannot be identified because no PDCCH istransmitted during SPS (occurrence of a lack of PUCCH resources).

In FIG. 17, the number of the PUCCH resource indexes associated with theTPC command for PUCCH included in the PDCCH on which the SPS activationis indicated, as PUCCH resource 1 (first PUCCH resource) used as aresource for SPS (explicit resource) is four (the same number as that ofLTE) set in advance by base station 100. Furthermore, as illustrated inFIG. 18, PUCCH resource indexes that are set as PUCCH resource 2 (secondPUCCH resource) used as a resource for SPS are indexes obtained byadding 1 to the PUCCH resource indexes associated with the TPC commandfor PUCCH. Accordingly, compared with the method illustrated in FIG. 9,in which new PUCCH resource indexes (fifth to eighth PUCCH resourceindexes in FIG. 9) are set in advance, the present embodiment can reducethe amount of signaling from base station 100 to terminal 200. In otherwords, in the present embodiment, the amount of signaling required toindicate the resources for SPS is the same as that of LTE (Release 8).

As described above, during dynamic scheduling, terminal 200 uses PUCCHresources (implicit resources) respectively corresponding to the top CCEindex (n_CCE) of the CCEs occupied by the PDCCH and the next CCE index(n_CCE+1) of the top CCE index. Meanwhile, during SPS, terminal 200uses: the PUCCH resource index (n⁽¹⁾ ^(PUCCH) ) associated with the TPCcommand for PUCCH included in the PDCCH on which the SPS activation isindicated; and the PUCCH resource index (n⁽¹⁾ ^(PUCCH) +1) obtained byadding 1 to the PUCCH resource index (n⁽¹⁾ ^(PUCCH) ). That is, for bothdynamic scheduling and SPS, terminal 200 uses a specific index (n_CCE orn⁽¹⁾ ^(PUCCH) ) and an index (n_CCE+1 or n⁽¹⁾ ^(PUCCH) +1) obtained byadding 1 to the specific index. That is, terminal 200 can adopt a PUCCHresource selecting method common to both dynamic scheduling and SPS.Accordingly, the process of selecting a PUCCH resource by terminal 200can be simplified.

In this way, according to the present embodiment, the amount ofsignaling from a base station can be reduced while a lack of PUCCHresources can be resolved during semi-persistent scheduling on PCellwhen a terminal is configured with a transmission mode that supports upto 2 TBs for PCell, while ARQ is applied to communications using anuplink component carrier and a plurality of downlink component carriersassociated with the uplink component carrier.

Note that, with regard to the method of indicating PUCCH resource 2 usedas a resource for SPS, the value to be added to the index of PUCCHresource 1 used as a resource for SPS is not limited to 1 and may be avalue of 1 or more (that is, natural number n). Furthermore, the valueto be added (natural number n) may be set in advance by base station100. Furthermore, when the maximum value of a PUCCH resource index isdefined, the remainder of the value divided by the maximum value afteradding 1 to the value may be used.

In the present embodiment, a description has been given of the casewhere a value (n⁽¹⁾ ^(PUCCH) +1) obtained by adding 1 to the PUCCHresource index (n⁽¹⁾ ^(PUCCH) ) associated with the TPC command forPUCCH is defined as the PUCCH resource index of PUCCH resource 2. Stateddifferently, in the present embodiment, a description has been given ofthe case where terminal 200 selects the PUCCH resource index of secondPUCCH resource 2 on the basis of the PUCCH resource index of first PUCCHresource 1. Alternatively, terminal 200 may select the PUCCH resourceindex of second PUCCH resource 2 on the basis of the transmission powercontrol information (TPC command for PUCCH) used for identifying firstPUCCH resource 1. That is, terminal 200 obtains second transmissionpower control information on the basis of first transmission powercontrol information (information indicated through PDCCH when SPS isactivated). For example, terminal 200 adds 1 to the first transmissionpower control information and uses the remainder of the value divided by4 after adding 1 to the value, as the second transmission power controlinformation. Terminal 200 selects a resource corresponding to the secondPUCCH resource index associated in a one-to-one correspondence with thesecond transmission power control information, as the second PUCCHresource (that is, second PUCCH resource 2).

For example, a description will be given regarding a case where the TPCcommand for PUCCH is ‘00.’ In this case, as illustrated in FIG. 17, thePUCCH resource index associated in a one-to-one correspondence with thefirst transmission power control information is “FIRST PUCCH RESOURCEINDEX.” Subsequently, the value ‘01’ obtained by adding 1 to the firsttransmission power control information ‘00’ is defined as the secondtransmission power control information. Accordingly, terminal 200identifies the PUCCH resource index associated in a one-to-onecorrespondence with the second transmission power control information‘01’ as “SECOND PUCCH RESOURCE INDEX” with reference to FIG. 17.Consequently, in the case where the TPC command for PUCCH is ‘00,’“FIRST PUCCH RESOURCE INDEX” is selected as PUCCH resource 1, and“SECOND PUCCH RESOURCE INDEX” is selected as PUCCH resource 2. The sameapplies to the case where the TPC command for PUCCH is other than ‘00’(‘01,’ ‘10,’ ‘11’). FIG. 19 illustrates a correspondence between the TPCcommand for PUCCH (that is, the first transmission power controlinformation) and the PUCCH resource index of second PUCCH resource 2.Specifically, terminal 200 selects first PUCCH resource 1 with referenceto FIG. 17 and selects second PUCCH resource 2 with reference to FIG.19.

The value to be added is not limited to 1 and may be 2 or 3. That is,the value to be added may be natural number m not greater than three.More specifically, terminal 200 may add natural number m to the value ofthe first transmission power control information (TPC command for PUCCH)included in the PDCCH on which the SPS activation is indicated. Then,terminal 200 may define, as the second transmission power controlinformation, the remainder of the value dividing by 4 (the number oftypes of the TPC command for PUCCH) after adding m to (that is, theremainder of the value divided by 4 after adding m to the value; mod((TPC command for PUCCH+1), 4)). Terminal 200 may define, as the secondPUCCH resource, a resource corresponding to the PUCCH resource indexassociated in a one-to-one correspondence with the second transmissionpower control information. Meanwhile, the value to be added (naturalnumber m) may be set in advance by base station 100.

During dynamic scheduling, a PUCCH resource (PUCCH resource 1 or 3(implicit resource) in the case of the present embodiment in which atransmission mode that supports up to 2 TBs is set for data assigned toPCell) in the uplink component carrier, associated in a one-to-onecorrespondence with the top CCE index of the CCEs occupied by the PDCCHindicating the PDSCH in a certain component carrier (any of PCell andSCell) may be expressed as n⁽¹⁾ ^(PUCCH,i) (i=0 or i=2, when atransmission mode that supports up to 2 TBs is set for the data assignedto PCell). Furthermore, in terminal 200 configured with a transmissionmode that supports up to 2 TBs for the data assigned to the certaincomponent carrier, a PUCCH resource (PUCCH resource 2 or 4 in the caseof the present embodiment) in the uplink component carrier, associatedin a one-to-one correspondence with the next index of the top CCE indexof the CCEs occupied by the PDCCH indicating the PDSCH in the certaincomponent carrier may be expressed as n⁽¹⁾ ^(PUCCH,i+1) (i+1=1 or i+1 =3when a transmission mode that supports up to 2 TBs is set for the dataassigned to PCell). Note that subscript x (i or i+1 in the above) addedto n⁽¹⁾ ^(PUCCH,x) indicates an index value of each PUCCH resource, andtakes a value of 0≤×≤A−1. “A” in the expression indicates the sum of themaximum numbers of TBs that can be supported in PCell and SCell and is avalue equal to the number of PUCCH resources.

Similarly, during SPS in PCell, the first resource for SPS (PUCCHresource 1 (explicit resource) in the case of the present embodiment inwhich a transmission mode that supports up to 2 TBs is set for dataassigned to PCell) may be expressed as n⁽¹⁾ ^(PUCCH,i) (i=0, when atransmission mode that supports up to 2 TBs is set for the data assignedto PCell). Furthermore, in terminal 200 configured with a transmissionmode that supports up to 2 TBs for the data assigned to PCell, thesecond resource for SPS (PUCCH resource 2 in the case of the presentembodiment) may be expressed as n⁽¹⁾ ^(PUCCH,i+1) (i+1=1 when atransmission mode that supports up to 2 TBs is set for the data assignedto PCell).

Meanwhile, during dynamic scheduling, for example, the PUCCH resourceindex (n⁽¹⁾ ^(PUCCH,i) ) associated in a one-to-one correspondence withthe top CCE index (n_CCE) may be expressed as n_CCE+N⁽¹⁾ ^(PUCCH) . N⁽¹⁾^(PUCCH) indicates a resource (index) set in advance by base station100. Similarly, the PUCCH resource (n⁽¹⁾ ^(PUCCH,i+1) ) associated in aone-to-one correspondence with the CCE index (n_CCE+1) may be expressedas n_CCE+1+N^((1)PUCCH).

The expression “during SPS in PCell” can also be expressed as, forexample, “during PDSCH transmission in PCell without a correspondingPDCCH.” Furthermore, the expression “during dynamic scheduling” can alsobe expressed as, for example, “during PDSCH transmission with acorresponding PDCCH.”

Embodiment 2

Hereinafter, a description will be given in detail with reference toFIG. 15, regarding a PUCCH resource indicating method during dynamicscheduling when the terminal is configured with 2 CCs and thetransmission mode that supports up to 2 TBs (transmission mode 3, 4, or8) for at least PCell. FIG. 15 illustrates an example of cross-carrierscheduling from PCell to SCell, however. More specifically, the PDCCH inPCell indicates the PDSCH in SCell.

PUCCH resource 1 in an uplink component carrier is assigned inassociation in a one-to-one correspondence with the top CCE index(n_CCE) of the CCEs occupied by the PDCCH indicating the PDSCH in PCell(implicit signaling). Moreover, PUCCH resource 2 in the uplink componentcarrier is assigned in association in a one-to-one correspondence withthe index subsequent to the top CCE index (n_CCE+1) of the CCEs occupiedby the PDCCH indicating the PDSCH in PCell (implicit signaling).

PUCCH resource 3 in the uplink component carrier is assigned inassociation in a one-to-one correspondence with the top CCE index(n_CCE′ (n_CCE′≠n_CCE)) of the CCEs occupied by the PDCCH in PCell thatindicates the PDSCH in SCell. PUCCH resource 3 is cross-carrierscheduled from PCell to SCell. Furthermore, when the terminal isconfigured with a transmission mode that supports up to 2 TBs(transmission mode 3, 4, or 8) for SCell, PUCCH resource 4 in the uplinkcomponent carrier is assigned in association in a one-to-onecorrespondence with the next index (n_CCE′+1) of the top CCE index ofthe CCEs occupied by the PDCCH indicating the PDSCH in PCell (implicitsignaling).

Note that the resource indicating method described above is an examplein which all the PUCCH resources are implicitly signaled, but thepresent invention is not limited to this example. All the PUCCHresources may be explicitly signaled. Alternatively, some of the PUCCHresources (for example, PUCCH resource 1 as well as PUCCH resource 3 atthe time of cross-carrier scheduling) may be implicitly signaled, andthe other PUCCH resources (for example, PUCCH resource 2 and PUCCHresource 4 as well as PUCCH resource 3 at the time of non-cross-carrierscheduling) may be explicitly signaled.

Next, a PUCCH resource indicating method during semi-persistentscheduling (SPS) when the terminal is configured with 2 CCs and thetransmission mode that supports up to 2 TBs (transmission mode 3, 4, or8) for at least PCell will be described in detail with reference to FIG.16, FIG. 17, and FIG. 18. FIGS. 16, 17 and 18 illustrate an example ofcross-carrier scheduling from PCell to SCell, however. Morespecifically, the PDCCH in PCell indicates the PDSCH in SCell.

Once SPS is activated, there is no PDCCH indicating a PDSCH for SPS inPCell, and hence PUCCH resource 1 and PUCCH resource 2 in the uplinkcomponent carrier, which are associated in a one-to-one correspondencewith CCE indexes, cannot be assigned. Accordingly, with regard to PUCCHresource 1, as illustrated in FIG. 17, one PUCCH resource index isselected from among the four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ) setin advance by the base station, on the basis of the value of thetransmission power control information (TPC command for PUCCH) in thePDCCH on which the SPS activation is indicated. PUCCH resource 1 in theuplink component carrier is assigned in accordance with the selectedPUCCH resource index.

With regard to PUCCH resource 2, as illustrated in FIG. 18, one PUCCHresource index is selected from among values (n⁽¹⁾ ^(PUCCH) +1) obtainedby adding 1 to the four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ) that areset in advance for PUCCH resource 1 by the base station, on the basis ofthe value of the transmission power control information (TPC command forPUCCH) in the PDCCH in which the SPS activation is indicated. PUCCHresource 2 in the uplink component carrier is assigned in accordancewith the selected PUCCH resource index. Note that, with regard to themethod of indicating PUCCH resource 2, the value to be added is notlimited to 1 and may be a value of 1 or more. Furthermore, the addedvalue may be set in advance by the base station. Furthermore, when themaximum value of a PUCCH resource index is defined, the remainder of thevalue divided by the maximum value after adding 1 to the value may beused.

In the embodiment described above, PUCCH resource 1 (that is, the firstPUCCH resource) is selected on the basis of the four PUCCH resourceindexes (n⁽¹⁾ ^(PUCCH) ) (that is, the first PUCCH resource index) thatare set in advance for PUCCH resource 1 by the base station on the basisof the value of the transmission power control information (TPC commandfor PUCCH) (that is, the first transmission power control information)in the PDCCH on which the SPS activation is indicated. In addition, thesecond PUCCH resource index can be obtained on the basis of the firstPUCCH resource index. PUCCH resource 2 (that is, the second PUCCHresource) is selected in accordance with the second PUCCH resourceindex.

Note that, in the embodiment described above, the PUCCH resource indexof PUCCH resource 2 is selected on the basis of values obtained byadding 1 to the four PUCCH resource indexes (n⁽¹⁾ ^(PUCCH) ).Alternatively, as illustrated in FIG. 19, the PUCCH resource index ofPUCCH resource 2 may be selected on the basis of the remainder (that is,mod (TPC command for PUCCH+1, 4)) obtained by: adding 1 to the value ofthe transmission power control information (TPC command for PUCCH) inthe PDCCH in which the SPS activation is indicated; and dividing theresultant value by 4. In this case, the added value is not limited to 1,and may be 2 or 3. Furthermore, the value to be added may be set inadvance by the base station. In this case, the second transmission powercontrol information is obtained on the basis of the first transmissionpower control information. The second PUCCH resource index and thesecond PUCCH resource are selected on the basis of the secondtransmission power control information.

The description regarding PUCCH resource 3 and PUCCH resource 4 is thesame as the description of dynamic scheduling in FIG. 15 and thus isomitted.

In this way, during dynamic scheduling or semi-persistent scheduling(SPS), terminal 200 selects a resource used for response signaltransmission from among the PUCCH resources associated with the CCEs andspecific PUCCH resources indicated in advance by base station 100, andcontrols the response signal transmission. Consequently, when configuredwith a transmission mode that supports up to 2 TBs for at least PCell bybase station 100, terminal 200 can solve a problem of a lack of PUCCHresources, which occurs during semi-persistent scheduling (SPS).Furthermore, compared with a method in which new four PUCCH resourceindexes (the fifth to eighth PUCCH resource indexes) are independentlyset in advance in addition to the first to fourth PUCCH resourceindexes, according to the present invention, PUCCH resource 2 (secondPUCCH resource) is selected on the basis of PUCCH resource 1 (firstPUCCH resource) (more specifically, on the basis of: the PUCCH resourceindex of PUCCH resource 1 (first PUCCH resource index); or thetransmission power control information (TPC command for PUCCH) (firsttransmission power control information) in the PDCCH in which the SPSactivation is indicated). Accordingly, setting the first to fourth PUCCHresource indexes only in advance is sufficient, so that the amount ofsignaling from the base station can be reduced.

During dynamic scheduling or semi-persistent scheduling (SPS), basestation 100 selects a resource used for response signal transmission,from among the PUCCH resources associated with the CCEs and specificPUCCH resources indicated in advance to terminal 200. In addition, whena transmission mode that supports up to 2 TBs is set for at least PCellby base station 100, during semi-persistent scheduling (SPS), basestation 100 selects the second PUCCH resource for SPS using thetransmission power control information (the value of the TPC command forPUCCH) or the PUCCH resource index, which is used to select the firstPUCCH resource for SPS.

In this way, according to the present embodiment, the amount ofsignaling from a base station can be reduced while a lack of PUCCHresources can be resolved during semi-persistent scheduling in PCellwhen a terminal is configured with a transmission mode that supports upto 2 TBs for PCell, while ARQ is applied to communications using anuplink component carrier and a plurality of downlink component carriersassociated with the uplink component carrier.

Embodiments of the present invention have been described above.

In the above described embodiments, ZAC sequences, Walsh sequences, andDFT sequences are described as examples of the sequences used forspreading. However, instead of ZAC sequences, sequences that can beseparated using different cyclic shift values, other than ZAC sequencesmay be used. For example, the following sequences may be used forprimary-spreading: generalized chirp like (GCL) sequences; constantamplitude zero auto correlation (CAZAC) sequences; zadoff-chu (ZC)sequences; PN sequences such as M sequences or orthogonal Gold codesequences; or sequences having a steep autocorrelation characteristic onthe time axis randomly generated by computer. In addition, instead ofWalsh sequences and DFT sequences, any sequences may be used asorthogonal code sequences as long as the sequences are mutuallyorthogonal or considered to be substantially orthogonal to each other.In the abovementioned description, the resource of response signals(e.g., A/N resource and bundled ACK/NACK resource) is defined by thefrequency position, cyclic shift value of the ZAC sequence and sequencenumber of the orthogonal code sequence.

Moreover, control section 101 of base station 100 is configured tocontrol mapping in such a way that downlink data and the downlinkassignment control information for the downlink data are mapped to thesame downlink component carrier in the embodiments described above, butis by no means limited to this configuration. To put it differently,even if downlink data and the downlink assignment control informationfor the downlink data are mapped to different downlink componentcarriers, the technique described in each of the embodiments can beapplied as long as the correspondence between the downlink assignmentcontrol information and the downlink data is clear.

Furthermore, as the processing sequence in terminals, the case whereIFFT transform is performed after the primary-spreading andsecondary-spreading has been described. However, the processing sequencein terminals is by no means limited to this sequence. As long as IFFTprocessing is performed after the primary-spreading processing, anequivalent result can be obtained regardless of the position of thesecondary-spreading processing.

In each of the embodiments, the description has been provided withantennas, but the present invention can be applied to antenna ports inthe same manner.

The term “antenna port” refers to a logical antenna including one ormore physical antennas. In other words, the term “antenna port” does notnecessarily refer to a single physical antenna, and may sometimes referto an antenna array including a plurality of antennas, and/or the like.

For example, 3GPP LTE does not specify the number of physical antennasforming an antenna port, but specifies an antenna port as a minimum unitallowing base stations to transmit different reference signals.

In addition, an antenna port may be specified as a minimum unit to bemultiplied by a precoding vector weighting.

The above-noted embodiments have been described by examples of hardwareimplementations, but the present invention can be also implemented bysoftware in conjunction with hardware.

In addition, the functional blocks used in the descriptions of theembodiments are typically implemented as LSI devices, which areintegrated circuits. The functional blocks may be formed as individualchips, or a part or all of the functional blocks may be integrated intoa single chip. The term “LSI” is used herein, but the terms “IC,”“system LSI,” “super LSI” or “ultra LSI” may be used as well dependingon the level of integration.

In addition, the circuit integration is not limited to LSI and may beachieved by dedicated circuitry or a general-purpose processor otherthan an LSI. After fabrication of LSI, a field programmable gate array(FPGA), which is programmable, or a reconfigurable processor whichallows reconfiguration of connections and settings of circuit cells inLSI may be used.

Should a circuit integration technology replacing LSI appear as a resultof advancements in semiconductor technology or other technologiesderived from the technology, the functional blocks could be integratedusing such a technology. Another possibility is the application ofbiotechnology and/or the like.

The disclosures of the specifications, drawings, and abstracts includedin Japanese Patent Application No. 2011-000744 filed on Jan. 5, 2011 andJapanese Patent Application No. 2011-233007 filed on Oct. 24, 2011 areincorporated herein by reference in their entirety.

INDUSTRIAL APPLICABILITY

The present invention can be applied to mobile communication systemsand/or the like.

REFERENCE SIGNS LIST

-   -   100 Base station    -   101, 208 Control section    -   102 Control information generating section    -   103, 105 Coding section    -   104, 107 Modulation section    -   106 Data transmission controlling section    -   108 Mapping section    -   109, 218-1, 218-2, 218-3 IFFT section    -   110, 219-1, 219-2, 219-3 CP adding section    -   111, 222 Radio transmitting section    -   112, 201 Radio receiving section    -   113, 202 CP removing section    -   114 PUCCH extracting section    -   115 Despreading section    -   116 Sequence controlling section    -   117 Correlation processing section    -   118 A/N determining section    -   119 Bundled A/N despreading section    -   120 IDFT section    -   121 Bundled A/N determining section    -   122 Retransmission control signal generating section    -   200 Terminal    -   203 FFT section    -   204 Extraction section    -   205, 209 Demodulation section    -   206, 210 Decoding section    -   207 Determination section    -   211 CRC section    -   212 Response signal generating section    -   213 Coding and modulation section    -   214-1, 214-2 Primary-spreading section    -   215-1, 215-2 Secondary-spreading section    -   216 DFT section    -   217 Spreading section    -   220 Time-multiplexing section    -   221 Selection section

What is claimed is:
 1. A communication apparatus comprising: atransmitter which, in operation, transmits downlink data to acommunication partner apparatus on a first component carrier and asecond component carrier, wherein a transmission mode is set to supportup to two transport blocks on the first component carrier; a receiverwhich, in operation, receives from the communication partner apparatus aresponse signal indicative of a plurality of error detection results ofthe downlink data, wherein, when a semi-persistent scheduling (SPS) isactivated for the first component carrier to periodically assignresources, the response signal is mapped to either one of a firstphysical uplink control channel (PUCCH) resource and a second PUCCHresource respectively indicated by a first PUCCH resource index and asecond PUCCH resource index, the first PUCCH resource index is a PUCCHresource index corresponding to a value of a transmission power control(TPC) command for an uplink control channel, and the second PUCCHresource index is another PUCCH resource index which is a value obtainedby adding 1 to the first PUCCH resource index; and a retransmissioncontroller which, in operation, retransmits the downlink data based onthe received response signal.
 2. The communication apparatus accordingto claim 1, wherein the first PUCCH resource index and the second PUCCHresource index are selected from a plurality of PUCCH resource indices.3. The communication apparatus according to claim 2, wherein: theplurality of PUCCH resource indices includes four PUCCH resource indices1-4 and the TPC command is indicated by two bits; when the value of theTPC command is 00, the first PUCCH resource index indicates PUCCHresource 1; when the value of the TPC command is 01, the first PUCCHresource index indicates PUCCH resource 2; when the value of the TPCcommand is 10, the first PUCCH resource index indicates PUCCH resource3; and when the value of the TPC command is 11, the first PUCCH resourceindex indicates PUCCH resource
 4. 4. The communication apparatusaccording to claim 1, wherein: the first component carrier is a primarycell (PCell), which is paired with an uplink component carrier on whichthe response signal is received; and the transmitter transmits thedownlink data on the second component carrier which is a secondary cell(SCell) different from the primary cell.
 5. The communication apparatusaccording to claim 1, wherein: the plurality of error detection resultsare a combination of an acknowledgement (ACK) indicating that an errorwas not detected, a negative-acknowledgement (NACK) indicating that anerror was detected, and a discontinuous transmission (DTX) indicatingthat reception of a downlink control signal has failed.
 6. Thecommunication apparatus according to claim 1, wherein: the TPC commandis included in downlink control information which indicates activationof the SPS.
 7. A communication method comprising: transmitting downlinkdata to a communication partner apparatus on a first component carrierand a second component carrier, wherein a transmission mode is set tosupport up to two transport blocks on the first component carrier;receiving from the communication partner apparatus a response signalindicative of a plurality of error detection results of the downlinkdata, wherein, when a semi-persistent scheduling (SPS) is activated forthe first component carrier to periodically assign resources, theresponse signal is mapped to either one of a first physical uplinkcontrol channel (PUCCH) resource and a second PUCCH resourcerespectively indicated by a first PUCCH resource index and a secondPUCCH resource index, the first PUCCH resource index is a PUCCH resourceindex corresponding to a value of a transmission power control command(TPC command) for an uplink control channel, and the second PUCCHresource index is another PUCCH resource index which is a valuegenerated by adding 1 to the first PUCCH resource index; andretransmitting the downlink data based on the received response signal.8. The communication method according to claim 7, wherein the firstPUCCH resource index and the second PUCCH resource index are selectedfrom a plurality of PUCCH resource indices.
 9. The communication methodaccording to claim 8, wherein: the plurality of PUCCH resource indicesincludes four PUCCH resource indices 1-4 and the TPC command isindicated by two bits; when the value of the TPC command is 00, thefirst PUCCH resource index indicates PUCCH resource 1; when the value ofthe TPC command is 01, the first PUCCH resource index indicates PUCCHresource 2; when the value of the TPC command is 10, the first PUCCHresource index indicates PUCCH resource 3; and when the value of the TPCcommand is 11, the first PUCCH resource index indicates PUCCH resource4.
 10. The communication method according to claim 7, wherein: the firstcomponent carrier is a primary cell (PCell), which is paired with anuplink component carrier on which the response signal is received; andthe communication method comprises transmitting the downlink data on thesecond component carrier which is a secondary cell (SCell) differentfrom the primary cell.
 11. The communication method according to claim7, wherein: the plurality of error detection results are a combinationof an acknowledgement (ACK) indicating that an error was not detected, anegative-acknowledgment (NACK) indicating that an error was detected,and a discontinuous transmission (DTX) indicating that reception of adownlink control signal has failed.
 12. The communication methodaccording to claim 7, wherein: the TPC command is included in downlinkcontrol information which indicates activation of the SPS.